Semiconductor Technology

t-gate and wafer
T-Gate of a 35nm Transistor (left) and a 4” Multi-Project Wafer with 300 GHz Rx/Tx MMICs (right).

35nm mHEMT Technology

Key enabling technology for the commercially viable implementation of communication systems at 300 GHz is the metamorphic HEMT (high electron mobility transistor) of the Fraunhofer IAF. As of today, the Fraunhofer IAF offers optimized mHEMTs with gate-lengths of 100 nm, 50 nm, 35 nm and 20 nm. The 35nm is selected in this project for its best compromise between cost, integration density and performance at 300 GHz.

  100 nm
50 nm 35 nm 20 nm
In content (%) 65 80 80 100
gm,max (mS/mm) 1300 1800 2500 2850
fT (GHz) 220 375 515 600
fmax (GHz) 300 600 ≈1000

High-frequency figure of merits of the Fraunhofer mHEMT technologies with different gate lengths and Indium content in the transistor channel.


Characteristic features of the mHEMT high speed technology at the IAF:

  • Indium Gallium arsenide (InGaAs) channel with high Indium content
  • Manufacturing on 4˝ semi insulating GaAs
  • Backside process and wafer thinning to 50 μm thickness
  • 20 μm diameter thru substrate vias
  • Multiple passive interconnection layers, MIM capacitors, NiCr resistors
  • Highly developed design kit models verified up to 500 GHz
  • Record noise figures and output power levels

The mHEMT technologies at Fraunhofer IAF are ideal candidates when broadband front-end MMICs are needed.

Further information

100 nm and 50 nm metamorphic HEMT technology

Leuther, A.; Tessmann, A.; Kallfass, I.; Losch, R.; Seelmann-Eggebert, M.; Wadefalk, N.; Schafer, F.; Gallego Puyol, J.D.; Schlechtweg, M.; Mikulla, M.; Ambacher, O. In: Indium Phosphide & Related Materials, 2009. IPRM '09. IEEE International Conference on , vol., no., pp.188-191, 10-14 May 2009


35 nm metamorphic HEMT MMIC technology

Leuther, A.; Tessmann, A.; Massler, H.; Losch, R.; Schlechtweg, M.; Mikulla, M.; Ambacher, O. In: Indium Phosphide and Related Materials, 2008. IPRM 2008. 20th International Conference on , vol., no., pp.1-4, 25-29 May 2008


20 nm metamorphic HEMT Technology

Leuther, A.; Koch, S.; Tessmann, A.; Kallfass, I.; Merkle, T.; Massler, H.; Loesch, R.; Schlechtweg, M.; Saito, S.; Ambacher, O. In: Compound Semiconductor Week (CSW/IPRM), 2011 and 23rd International Conference on Indium Phosphide and Related Materials , vol., no., pp.1-4, 22-26 May 2011